Help: Question about Canon 500d close up filter/lens

[NateS]

I'm trying to figure out what the 500d will give me in magnification. With my Sigma 70-300 APO DG Macro, I am at 1:3 at 200mm and 1:2 at 300mm. Ideally I'd like to use this closeup filter at 200mm since the lens is considerably sharper at 200mm than 300mm.

So, is there anyway to figure out what my magnification ratio will be with the Sigma at 200mm and 300mm with the 500d attached?

Also considering getting rid of the Sigma to get a Nikon 55-200VR to do this with....it is 1:4, but again, I have no way of knowing if the 55-200VR with 500d will be greater than the 1:2 I'm getting now with my Sigma 70-300 APO.

For what it's worth, Canon lists the 500d as a diopter +2, but I have no idea what that means. I appreciate any help.

 

[kundalini]

This won't really help with the numbers you're after, but it may help a little with interests.

[video=youtube;U7rrEQxjHmA]http://www.youtube.com/watch?v=U7rrEQxjHmA"]Bryan Peterson[/video]

 

[NateS]

Thanks Kundalini. That doesn't really help cause I've been viewing some awesome stuff done with the 500d and a few looked like they were pretty close. I saw one with the 500d on a Nikon 55-200 and they were some really nice shots...however I couldn't tell if they were closer than what I can currently shoot or not.

That video was kind of funny in the fact that I do have a Macro fund and was planning to spend $85 to get the 500d (in the 58mm size) to use on my Sigma.....plus I could get a step up ring to use it with the Tamron 90mm f2.8 when I get it to be closer than 1:1. However, I'd like to know where it puts me and to be honest, I'm more interested in how close to 1:1 it will make a 55-200VR which is normally 1:4.

I'm planning to purchase this lens either way, but would like to know if I'd be better served by ditching the Sigma 70-300 APO (Still an incredible lens for the money) in exchange for the 55-200VR.

To give an idea of my current close focus abilities. Look at the picture below for reference.

Now this is at 1:2 and 300mm

I would like to be able to get close enough to fill the frame with that bug, and call me greedy, but I'd like to be able to do that at 200mm (which is 1:3 right now) since the lens is a lot sharper at 200mm.